A Physiological Role of Epidermal Growth Factor in Male Reproductive Function

TLDR

Epidermal growth factor, produced in large amounts by the submandibular gland of mature male mice and present at ~5 ng/mL in plasma, is known to stimulate cell proliferation in culture but its physiological role remains unclear. Removing the submandibular glands eliminates circulating EGF, reduces epididymal sperm by up to 55 % and testicular spermatids by 40–50 %, while EGF treatment restores these counts, indicating that EGF promotes the meiotic phase of spermatogenesis.

Abstract

Epidermal growth factor (EGF) stimulates the proliferation of various mammalian cells in culture, but its physiological role is not well defined. In mature male mice, large amounts of EGF are produced in the submandibular gland; it is present in the circulation at approximately 5 nanograms of EGF per milliliter of plasma. Sialoadenectomy (removal of the submandibular glands) decreased the amount of circulating EGF to an undetectable level but did not affect the circulating levels of testosterone or follicle-stimulating hormone. The number of mature sperm in the epididymis decreased by as much as 55 percent; the number of spermatids in the testis decreased by 40 to 50 percent; and the number of spermatocytes increased by about 20 percent. Administration of EGF to sialoadenectomized mice restored both the sperm content of the epididymis and the number of spermatids in the testis to normal. Thus, EGF may play a role in male reproductive function by stimulating the meiotic phase of spermatogenesis.